Gam3r01 :
Cards dont gain performance from then to now.
The 760 performs the same then as it would now, same for the 7950. Old benchmarks reflect older cards.
NEW benchmarks, including new cards, still has 8% higher performance
http://www.techpowerup.com/reviews/Gigabyte/R9_280X_OC/26.html
its a 7950=280, not a 7970=280x
but that benchmark now shows a 760@915 and a 7950@800 and the difference dropped to 4%, instead of a 760@980 and a 7950@800 which was an 8% difference.
800x1.05=840..... 800x1.08=864..... 1100x1.08=1188
we all know for a fact that tahiti overclocks much better than gk104, tahiti held world records across all measures until titan. also dependent on the pcb design, some cards will overclock better. clock for clock, tahiti 7950/280 1792core is roughly 8% faster average than a 760 1152 core.
this is in arguable. and i own an nvidia card too so its not fanboy stuff, its math, statistics, and user input. doller=dollar, the 7950 has mantle too which will give it about a 4-7% increase in these mantle enhanced games.